1. Field of the Invention
The invention relates to a transformer having an output coil integrally formed therewith.
2. Description of the Related Art
FIG. 12 shows a configuration of a transformer core including two integrated transformers, as disclosed in Japanese Unexamined Patent Publication No. 2005-51995. An I-shaped core 3000 is disposed on an E-shaped core 2000 and a first side wall 2003, and a gap G101 is formed between the I-shaped core 3000 and a center column 2002. Accordingly, a first gap closing magnetic circuit 6000 is formed to pass through the I-shaped core 3000, the first side wall 2003, a bottom plate 2001, the center column 2002, the gap G101 and the I-shaped core 3000. The gap closing magnetic circuit 6000 is a magnetic circuit for a transformer T101. An I-shaped core 4000 is disposed on the E-shaped core 2000 and a second side wall 2004, and a gap G102 is formed between the I-shaped core 4000 and the center column 2002. Accordingly, a second gap closing magnetic circuit 7000 is formed to pass through the I-shaped core 4000, the second side wall 2004, the bottom plate 2001, the center column 2002, the gap G102 and the I-shaped core 4000. The gap closing magnetic circuit 7000 is a magnetic circuit for a transformer T102.
Primary windings W101 and W104 are formed integrally, and wound around the center column 2002 by a specified number of turns. Similarly, primary windings W102 and W105 are formed integrally, and wound around the center column 2002 by a specified number of turns. Coils W103 and W106 constituting secondary windings are wound on the center column 2002 in a reverse direction by a half turn. Thus, a common transformer is formed by integrating transformers T101, T102.
As other related techniques, there are known the DC-DC converters as disclosed in Japanese Unexamined Patent Publication No. 2005-51994, Japanese Unexamined Patent Publication No. 2003-79142, Japanese Unexamined Patent Publication No. 2002-57045 and Japanese Unexamined Patent Publication 2000-353627.